The overall hypothesis of this proposal is that elevated sex steroid levels may account for some of the hormone related conditions that follow throughout life in African American females, including leiomyomas, endocrine related cancers, and protection from osteoporosis. If so, we may then begin to understand their contribution to these processes, both protective and additive in Black females. This will form the basis for better understanding these conditions in all females, and also will allow us to amend our preventive strategies to prevent these morbidities. We propose to both quantify differences in sex steroid levels in the normal menstrual cycle, as well as to identify mechanisms. We further propose to examine the effects of sex steroids on an end organ-in this case bone mineral density and architecture.